Disabling Unused Clocks

[jaredm]

We are developing hardware using the RT1052 and a subset of its peripherals. We are using MCUXpresso to configure the clock tree and would like to disable clocks that are unused. For instance, we are not using ENET, LCDIF, SPDIF, SAI, etc. We are looking for the best practice to disable unused clocks and are considering the following options:

1. Gating: The Clocks Tool does not appear to include clock gating information, i.e. CCGR registers. Is there another place where these registers are configured, or must they be written to manually?
2. Inactive: Some clocks can be effectively disabled by selecting inactive clock sources. For example Inactive CLK1 can be routed through multiplexers to ENET which will become Inactive. Is this recommended, or does it cause problems with to upstream / downstream logic considerations?

[gusarambula · Accepted solution]

Hello jaredm,

The following Knowledge Base document may be of help, specifically section 3 (Low Power Gating unit LPCG)

https://community.nxp.com/t5/i-MX-RT-Knowledge-Base/RT-s-System-Clocks/ta-p/1151118

The root clocks are branched to each peripheral, and these are individually gated clocks so you would be interested in gating the branch for your module, not the clock of origin.

I hope that this information helps!

Regards,
Gustavo